Automatic control for air to be heated in air-heating furnaces



y 8, 1951 c. LUND 2,551,956

AUTOMATIC CONTROL FOR AIR TO BE HEATED IN AIR HEATING FURNACES Filed May16, 1946 2 Sheets-Sheet 1 INVENTOR CLARENCE L.LUND

ATTRORNEY May 8, 1951 c. L. LUND AUTOMATIC CONTROL FOR AIR TO BE HEATEDIN AIR HEATING FURNACES 2 Sheets-Sheet 2 Filed May 16, 1946 Patented May8, 1951 AUTOMATIC CONTROL FOR AIR TO BE HEATED IN AIR-HEATING FURNACES.

Clarence L. Lund, Oshkosh, Wis, assignor of onehalf to R5. T'eela,Oshkosh, Wis.

Application May 16, 1946, Serial No. 670,195

1 Claim. 1

My invention refers to automatic air control for furnaces and it has forits primary object to provide an overbalanced butterfly valve inalignment with the air. passage to a. furnace, whereby a blast of air isdischarged against the long vane of a butterfly valve, under control, ofa blower, when the temperature of the furnace airreaches a predeterminedhigh degree. Thus the volume of air is increased by starting the motordrive of the pump or. fan, when an electric circuit is closed through athermostatic switch.

When the temperature of the furnace air drops the thermostat switch willbreak the circuit, whereby the pump orv fan comesto rest and the airfrom the room pipes, or other source, will be drawn into the furnace,under normal conditions, for circulation to the rooms.

A further object of my invention is to provide air control to thefurnace, whereby under forced draft conditions the air is thoroughlyfiltered.

A further object of my invention is to provide a butterfly valve withfine adjustments, whereby the normal air draft is cut off when theforced draft is in use.

With the above and other objects in view, which will appear as thedescription proceeds, the invention resides in the novel construction,combination and arrangement of parts, substantially as hereinafterdescribed, and more particularly defined by the appended claim, it beingunderstood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claim.

In the accompanying drawings is illustrated one complete example of thephysical embodi- I ment of the present invention constructed accordingto the best mode so far devised for the practical application of theprinciples thereof.

In the drawings:

Figure l is a side elevation of a furnace and air equipment embodyingthe features of my invention, the same being partly in section asindicated by line |l of Figure 2.

Figure 2 is a plan sectional elevation the same being indicated by line2-2 of Figure 1, and

Figure 3 is a fragmentary cross section through the valve mechanism, thesection being indicated by line 3-3 of Figure 1.

Referring by character to the drawings l indicates a dome, having an airpipe 2 communicating therewith, leading from rooms in a building. 3 is afresh air funnel, also leading into the dome, it being understood thatthese feeder pipe may be valve controlled.

The open bottom of the dome communicates 2 with the top portion of atrunk or easing 4, having removable filter screens 5, extending acrosssaid upper portion of the trunk or casing, the filter screens aresupported by angle iron flanges 6.

Spaced from the trunk or casing t, is an air expansion valve chamber "I,which chamber at its lower end is provided with an air. delivery mouththat discharges into the air jacket 8, of a furnace. The upper portionof the furnace is provided with the usual hot air pipes 8., and athermostatic switch 9, of the mercury type.

The upper end of the valve chamber 1 is connected to the dome l, by ahousing Ill, whereby air is discharged into the chamber from the roompipes 2-, or funnel 3, under normal circulation.

The valve chamber 7 and trunk or casing- 4, at their lower portions, areconnected by a flexible duct II, the same being in horizontal alignment,with the air delivery mouth 1, of said chamber.

The thermostatic switch 9, is electrically con nected by wires 9 to linewires 9", which line wire supply current to the driving motor I2, of ablower fan It, as indicated in Figures 1 and 2 of the drawings.

The blower fan is encased in the trunk or casing 4, below the filterscreens thereof and said fan discharges directly into the flexible ductll.

Owing to the flexible duct connection between the trunk or casing A andexpansion valve chamber i, it will be noted that said flexibility isprovided for the purpose of absorbing vibration from the blower fan.

The chamber i has journaled in its side walls a shaft [4, upon whichshaft is mounted a butterfly valve I5. The valve is frictionally held tothe shaft by a simple strap 16 having tension adjustable clip portionit, which encases the shaft.

It will be noted that the lower vane of the butterfly valve is ofmaterially greater length or area than the upper vane portion and saidlower Vane extends downwardly into the line of travel of air from thedischarged duct 4, to the delivery air mouth I.

The ends of the valve shaft extend beyond the side walls of the chamberi and have mounted thereon, oppositely disposed rods [1, havingadjustable counterbalanced weights l! thereon.

By this adjustable weight feature, the valve is finely controlled as tobalance, whereby it is sensitive to the current of air traveling throughthe bottom of the chamber '5, thus when the air strikes the lower vaneof the Valve it will cause the fan to move in an angularposition, asindicated in dotted lines of Figure 1. In this dotted position the valveends will set upon transversely disposed angle irons [8, I8, secured tothe end wall and the top edge of the delivery mouth 1 of the chamber,whereby the upper portion of said chamber and housing I will be cut 01ffrom the lower portion of the aforesaid chamber to discharge air fromthe fan directly into the furnace mouth.

From the foregoing description it is apparent, when the temperaturerises to a predetermined degree in the furnace air jacket, the mercury.switch will close the circuit 9 and line wire circuit 9", whereby themotor 12 will start the fan or blower l 3, it being understood that themake or break switch 52 in the line wire circuit, at this time, isclosed.

The forced draft current of air from the fan, will exert pressure uponthe lower vane of the valve, whereby said valve will swing to its closedposition. In this closed position the normal current of air from thedome I, to the furnace is cut off and said air from the dome and roompipes will then travel downwardly, through the trunk filter screens, tobe forced in a large volume, into the furnace, to thus increase itsutility, whereby the circulation of hot air into the rooms, ismaterially increased.

I claim:

In a hot air furnace having a bottom air inlet mouth; an air controllingapparatus for the furnace, comprising an air chamber having its lowerend in communication with the furnace mouth, an air dome incommunication with the top portion of the chamber, air supply pipescommunicating with the dome, a casing communicating with the bottom ofsaid dome, an air duct in the bottom of the casing communicating withthe chamber and aligned with the furnace mouth, a gravity controlledbutterfly valve pivoted in the chamber, the pivotal axis of said valvebeing disposed above the furnace mouth and casing duct,

said valve having an upper hort vane and a lower long vane, said lowerlong vane, due to gravity, functioning to normally hold the valve biasedin an open vertical position with said long vane in the path of airtravel from the casing duct, said valve being movable to an inclinedclosed position when the long vane is swung upward for closing offcommunication between the chamber and the dome and the furnace mouth andduct connecting the chamber to the casing, a motor driven fan in thecasing having a discharge communicating with the air duct, connectingthe casing and chamber, a thermostatic switch encased within the hot airjacket of the furnace, electric supply wires connecting the thermostaticswitch and motor, whereby when the furnace develops a high temperature,the switch closes the electric circuit to start the motor and cause airfrom the dome to be delivered to the furnace under forced draft, throughthe casing duct and furnace mouth and exert pressure upon the long vaneof the valve, to cause the same to rock and close the chamber above thefurnace mouth and cut off normal flow of air from the dome supply pipesto the furnace and establish a forced draft from said dome supply pipes,through the casing and its duct into the furnace mouth.

CLARENCE L. LUND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

